Field of the Invention
The invention relates to controlling a wireless transceiver, and more particularly to establishing control and performance parameters based upon a determination of jurisdiction.
Description of the Related Art
In recent years, the use of wireless and RF technology has increased dramatically in portable and hand-held units, with them not only widespread, but increasingly pervasive, as with their uses including telephony, Internet e-mail, Internet video, Internet web browsers, global positioning, photography, navigation systems, in-store navigation, and linking peripherals to host devices. The number of cellular telephone subscribers alone worldwide is expected to reach 3 billion by the end of 2008, up from 2.1 billion in 2005, according to the International Telecommunication Union (ITU). In 2006 the number of cellular phone subscribers exceeded 200 million within the United States of America.
Similarly the devices incorporating wireless technology have expanded, and continue to so, including today not only cellular telephones, but Personal Digital Assistants (PDAs), laptop computers, palmtop computers, gaming consoles, wireless local area networks, wireless hubs, printers, telephone headsets, portable music players, point of sale terminals, global positioning systems, inventory control systems, and even vending machines. These wireless devices interface to wireless infrastructures that can support data, voice and other services on either single or multiple standards, and where these international standards also have geographic aspects to providing a wireless device operating in compliance with the standard. Typical examples of wireless standards in significant deployment today include but are not limited to:                WiFi [ANSVIEEE Standard 802.11];        WiMAX [IEEE Standard 802.16];        Bluetooth [IEEE Standard 802.15.1];        ZigBee [IEEE Standard 802.15.4];        Industrial, Scientific and Medical (ISM) [International Telecommunications Union Recommendations 5.138, 5.150, and 5.280]; and        GSM 850/900/1800/1900 [European Telecommunications Standards Institute (ETSI)] and it's extensions General Packet Radio Service (GPRS) and Enhanced Data rates for GSM Evolution (EDGE).        
Of these, GSM service is used by over 2 billion people across more than 212 countries and territories. The ubiquity of the GSM standard makes international roaming practical between mobile phone operators, enabling subscribers to use their phones in many parts of the world, with the geographic coverage determined according to whether the cellular telephones are dual, tri-band or quad-band. WiFi (WLAN) communication has also enjoyed overwhelming consumer acceptance worldwide, generally as specified in IEEE 802.11a (operating in the frequency range of 4900-5825 MHz) or IEEE 802.11b and IEEE 802.11g specifications (operating in the range 2400-2485 MHz). These standards seem destined to survive and thrive in the future, for example with the IEEE 802.11n MIMO physical layer. The 802.11 value proposition is the provision of low cost, moderate data communication/transport rates and simple network function.
WiMAX (WMAN) communication is also preparing to deploy massively worldwide, especially as IEEE 802.16e (operating at two frequency ranges, the first being 2300-2690 MHz, and the second of 3300-3800 MHz). The IEEE 802.16e value proposition is the provision of moderate cost and data communication 1 transport rates with high quality of service, which requires higher system performance and complexity.
Whilst the general systems are covered by umbrella specifications, such as IEEE 802.11 (WiFi), and GSM, the standards provide for variations in performance that may be at the continental, country, and regional level. For example, GSM utilizes the 900 MHz/1800 MHz bands across Europe whilst coverage in North America exploits the 850 MHz/1900 MHz bands due to legacy infrastructure operating in these other bands. Similarly, WiFi (IEEE 802.11) is strictly 802.11a, 802.11b and 802.11g with 802.11n in development. IEEE 802.11a operating in the frequency range of 4900-5825 MHz has regional variations such that Japan provides 11 channels within two frequency bands, Europe 19 channels within 2 frequency bands, and North America 23 channels across 4 frequency bands.
What is not generally evident to even so-called knowledgeable users is that whilst some frequency bands are common, for example channels 36-48, 52-64, and 102-140 in both North America and Europe, the performance specifications for the transmitters within the two territories are different in respect of allowed maximum transmitter output power, band edge rejection to neighboring channels, and levels of harmonics. Accordingly, a manufacturer of an electronic device capable of operating within both jurisdictions, and transferred arbitrarily between them, must make the transmitter compliant to both. Within current high volume commodity electronics, an efficient solution is to provide a device that is compliant to the minimum common overlap within the specifications of the two jurisdictions.
For example, consider an electronic device operating according to IEEE 802.11a, and the sub-set of channels 36-64, having centre frequencies between 5180 MHz and 5320 MHz. For channels 36 to 48 in North America, FCC regulations as described in CFR47, part 15, section 15.407, provide for a maximum conducted transmitter output power of +16 dBm, and on channels 52-64 an output power of +23 dBm. In contrast, Europe provides a maximum output power of +23 dBm EIRP for all these channels. Since antenna gains are approximately 4 dBi for most 802.11a radios, the maximum allowed transmit power in Europe will therefore be approximately 19 dBm. Hence, designing the system to ensure compliance to channels 36-64 in both jurisdictions results in establishing the maximum output power of the transmitter at +16 dBm, since the selection of the channel that the device will employ will depend not only upon which jurisdiction it is within but also local infrastructure deployed and current channel assignments. As such, the device will be operating in Europe at 3 dB lower output power, and in North America for channels 52-64 at 7 dB lower output power than specifications allow. The result is a device that, whilst compliant and operating in all jurisdictions, will provide the user with either reduced range from a base station, increased dead zones from lack of available base stations, or reduced data rates for data transfer.
Clearly, whilst the manufacturer trades optimum performance within each jurisdiction for simplicity of manufacture, global distribution of single common assembly, and confidence III compliance with the jurisdictions, the user suffers unnecessary performance limitations affecting their use of the electronic device, wireless electronics, etc. in general and potentially reduced satisfaction with the manufacturers' brand.
It would therefore be desirable to provide an electronic device to automatically determine the jurisdiction under which it is currently operating, and to therefore adjust the control settings of the wireless transmitter accordingly for improved performance, whilst ensuring compliance with local jurisdiction regulations and requirements. Further, it would be advantageous for the electronic device to do so without interacting with the local network to either avoid non-compliant transmissions during set-up within a new jurisdiction or allow existing communications to continue without interruption as the jurisdiction changes with the users' movements.